This kind of device is often used to secure beach umbrellas and essentially consists of a bar that has a lower end that is designed to be driven into the ground; said bar generally comprises a helical projection that makes it easier to secure it in the sand by twisting the bar while at the same time exerting a small amount of axial pressure thereupon.
Examples of this kind of devices are described in USP 20050211282, USP 20060272687, or USP 20080099061.
The devices are often produced by adding an attached plastic tip to the end of a hollow rod, whereby this tip is produced by injection of plastic. This makes it possible to sell them at very reasonable prices. This design is, however, not very strong.
A different, sturdier design involves soldering on a flanged helical structure along a metal tip that is mounted at the end of a hollow rod. This design is much stronger but at the same time costs more to manufacture, and therefore it is used only in applications that require high quality and performance.
These devices are suitable for securing rods in very soft ground, for example, the sand on a beach, but they are not suitable when the ground is not beach sand, e.g., compacted earth, since the force required to drive them into the ground would greatly exceed the strength of the material and they would certainly break after being driven into the ground a few times. Moreover, their shape has the effect that it is necessary to exert a great deal of thrust and torsion, thus making it impossible to drive them in by hand.